Heres the catch when hitec sells u advanced programmable servos , they want u to buy their programmer . thats why they have built in a whole range of flexible options . the dead band allows one to change the width of the neutral point , to avoid servos fighting one another when two or more are used on one surface. when u have a wider deadband u can actually move the servo arm abt 1mm each side ( no not slop but it moves like a damper kinda effect) it moves upto a point before it starts humming and the motor takes over to counter the torque. when u have the tightest deadband width , the moment u try to move the servo arm at neutral , the motor takes over and produces counter torque , ull kno cause it starts humming. its an amazing feature that enables u to finetune multiple servos on one surface, even if one servo is used per control surface and the deadbands r not evenly matched u wont have tru presice control . and no matter what hitec tells u its very hard to find two 5955 with similar default values , I kno cause i just finished programing 14 of them in a 3.3m yak.